496 THE EOCENE PERIOD. 



Meniscotherium terr^rubr^ Cope. 



Paleontological Bulletiu No. 33, p. 493, Sept. 30, 1881. Proceed. Amer. PliUos. Soc, 1881, p. 493. 



Plate XXV/, figs. 12-14: XXV 3. 



I have parts of skeletons of many individuals of this animal, but each 

 one in a very imperfect condition. It is practicable from these to learn the 

 osteology of the species, but in using the measurements it must be borne 

 in mind that there is some range of variation in the different individuals. 



A specimen with both jaws crushed in a limestone nodule displays two 



superior incisors. They are short, and a little expanded laterally. The 



second has median angle and an external oblique edge. On the third the 



apex is at the internal angle, and the edge is all external and oblique. 



Surface smooth. 



Measurements of incisors.. 



M. 



Length of crown of superior I. i 004 



Width of crown of superior 1 004 



Length of crown of superior I. ii 005 



Width of crown of superior I. ii 004 



Length of inferior true molars of same 025 



In a second specimen the superior molar series is most complete. 



The dimensions of the superior molars increase to the penultimate, 

 while the external and posterior sides of the last molar are contracted, re- 

 ducing its size. The external faces of the external Vs of the true molars 

 are considerably impressed; those of the premolars are nearly flat. 



The second premolar is two-rooted, and has a compressed crown, with- 

 out either heel or cingulum, except a thickening of the posterior base. 

 The base of the crown is triangular. The external plate of the third pre- 

 molar is simple, and is connected with the internal cusp by a cingulum on 

 the posterior base of the crown. The crown is transverse, and the inner 

 tubercle rather small. Tlie fourth premolar is much larger than the third. 

 Its external plate is divided into two apices, which are not impressed. 

 Their external faces are separated by a faint ridge and are divided medially 

 by a faint ridge. The anterior external angle is rather prominent. The 

 anterior and posterior cingulum extend to and round the inner base of the 

 interior tubercle. Within the anterior external apex is a well-developed 

 intermediate crest parallel to it; and there is a corresponding crest within 



